Nothing wrong with a basic milspec lower, but if you have the budget make life a little easier and better and go "milspec+" or better, to a factory ambidextrous lower like SanTan.
By "milspec+" I'm refering to a relatively basic forged lower that has added features. I like upper-tensioning screws to tighten things up. I also like eliminating wear points when possible. This made me buy the Tactical Innovations matched set. They have tensioning screws and they proprietary "STBA." That is a set of stainless inserts that create a steel-on-steel condition for the FCG pins, instead of steel-on-aluminum. They also come with a captured rear takedown detent. If you ever shoot a few of those across a room, never to be found agan, the captured versions are a Godsend. Added advantage to them is you can adjust the force needed to move the rear takedown pin by tightening or loosening the plug that holds it in.
So any of these cost a bit more, but if you can get the upgrades built in for not a lot more you really will appreciate them. And, for the record, no, I don't work for them.